10W-30 Synthetic OK year around?

[zulu]

Just moved to Kansas from Texas, and I've been running 10w30 synthetics all year around in TX in my RSX, and now my new Malibu (2.4 Ecotec). Kansas winters get down to single digits only a couple times per year. Mostly teens and twenties average. Do I need to drop down to 5w30, or is 10W synthetic still okay?

 

[salesrep]

The 10-30 will work just fine in your new climate.

 

[MGregoir]

Above 0F 10w30 is acceptable, GM listed it in the manual at least until fairly recently.

 

[Drew99GT]

Synthetic 10w30 is easily doable below 0, but synthetic 5w30 is even better. It'll get to 20 below in Kansas several times a decade, especially northern Kansas. I'd personally switch to 5w30 for winter, but it's likely not totally necessary - most cars would be cranking away at 20 below with bulk conventional 10w30.

 

[MGregoir]

It's not the cranking, it's the poor flow. I find most conventionals are unhappy being pumped around, even in a 5w30, starting in the -10 Fahrenheit range.

I would say 0F is a reasonable cutoff for any 10w30. The synthetic helps improve things but you have to consider that if it were that much better than 10w30, it'd be 5w30 or 0W-30.

 

[Drew99GT]

If you look at data sheets though, many 10w30 synthetics pump equal to conventional 5w30s at -35C. Pennzoil Platinum 10w30 pumps 10,000 cP at -30C (would roughly be around 20,000 cP @ -35C). Most Conventionals 5w30s are around 20,000 cP @ -35C.

In actuality, cold pumping is where synthetics have the advantage. With a limit of 60,000 cP cold pumping for each W grade, pretty much all synthetic and most conventional 10w30s will pass the 5w cold pumping test, where as no conventional and hardly any synthetic 10w30s will pass the 5w cold cranking test.

 

[Steve S]

Unless you live in the arctic circle.

 

[PT1]

Pennzoil Platinum 10w30 would serve you well. I have run it in the winters here in Ohio. Pumps right up at -10F.